The main goal of this project is
to develop a new technique to fabricate the
coherent porous silicon (CPS) wick and
integrate it into the micro loop heat pipe
(micro-LHP). Another goal is to optimize the
pore size, pitch, porosity and wick
thickness to maximize the heat flux and
capillary pressure in the device. Through
control of pore size, the flow resistance of
the micro-LHP will be defined. Finally, the
novel design of the CPS wick will
significantly increase the efficiency of
micro-LHP while preventing the severe
problems such as bubble formation, liquid-
vapor interface oscillation, and wick dry
out. The micro-LHP is a two phase thermal
ground plane device for chip-level,
integrated cooling. This system draws
significant heat flux from electronics when
the operating fluid changes to the vapor
phase. The porous wick, a key component of
the micro-LHP, is located between evaporator
and reservoir and it serves as the engine
which achieves continuous fluid circulation.
It feeds coolant to the evaporator surface,
determines the capillary pumping capability
of the overall micro-LHP system and serves
as thermal barrier between the coolant
channels and evaporator chamber. The
traditional sponge-like porous wicks have a
randomly distributed pore size and irregular
flow path. On the contrary, three-
dimensional porous structures made via ion-
track etching, photolithography, and replica
molding have complex fabrication process and
restrictions on the device design.